本文針對海岸山脈安山岩進行鹼-骨材反應特性及抑制方法的研 究，以調整鹼含量及海岸山脈安山岩含量的方式，進行水泥砂漿棒 膨脹試驗（ASTM C227）、混凝土角柱試驗（ASTM C1293），探討 海岸山脈安山岩在鹼-骨材反應過程中的膨脹特性。並利用飛灰和爐 石兩種波索蘭材料分別置換水泥砂漿棒及混凝土角柱中部份水泥 量，以探討抑制海岸山脈安山岩鹼-骨材反應的成效。此外，針對花 東海岸線的混凝土消波塊進行現地調查及鑽心取樣工作，並進行醋 酸鈾試驗及相關分析。 根據研究結果發現，海岸山脈安山岩具有明顯的鹼-骨材反應， 改變水泥砂漿棒及混凝土角柱中海岸山脈安山岩含量，發現悲極值 （pessimum）的存在，安山岩悲極比例約為50%。此外，骨材中只 要有少量海岸山脈安山岩，即可使膨脹應變量大幅增加，產生危害 性的膨脹量。 以飛灰和爐石兩種波索蘭材料抑制海岸山脈安山岩的鹼-骨材反 應，可以得到明顯的效果，飛灰和爐石取代水泥比例愈高，抑制效 果愈佳，而抑制效果會因波索蘭材料置換水泥的比例、波索蘭材料 種類、反應性骨材的種類及試體中的鹼含量不同而異。 本文對花東海岸線濱海地區進行鹼-骨材反應案例之現地調查及 鑽心取樣分析，發現調查地點之混凝土消波塊具有鹼-骨材反應的多 項特徵，包括：不規則地圖狀裂縫、貫穿骨材裂縫、出現反應膠體、 骨材邊緣發生暗色或淺色的反應圈等。此外，將鑽心試體切片進行 醋酸鈾螢光試驗，沿裂縫處或安山岩骨材周圍常出現淡黃綠色的螢 光反應，可作為鹼-骨材反應生成物膠體存在的佐證。從前述各種徵 象綜合研判，調查地點混凝土消波塊之劣化應與鹼-骨材反應有關。 The main goal of this article is to investigate the characteristics of alkali-aggregate reaction of andesites from coastal range and search for a solution. In order to inhibit this kind of phenomena, two methods provided here include the adjustment of alkali contents and andesites’ contents in mortar bar test （ASTM C227）as well as concrete prism test （ASTM C1293） in order to study the expansion of this reaction. Furthermore, the cement used in ASTM C227 and ASTM C1293 were replaced with different amounts of fly ash and slag to prevent an alkali-aggregate reaction. In addition, samples of the drilling core of precast concrete blocks were obtained from Hualien-Taitung seaside and analyzed using by uranyl acetate fluorscence method. Based on our results, we have observed an obvious change in the alkali-aggregate reaction of andesite from coastal range. Also we have found that the pessimum content of andesite is around 50% when the amount of andesite in mortar bar and concrete prism was changed. Moreover, a small amount of andesite from costal range will create the expansion dramatically and cause damage. Thus the addition of fly ash and slag （pozzolan materials） will inhibit the alkali-aggregate reaction of andesite from the coastal range. It is also obvious that the better inhibition will be obtained when a higher content of fly ash and slag is in the concrete. The occurrence of the inhibition effect is based on the ratio of the contents of pozzolan materials in concrete, the kinds of pozzolan materials , reactive aggregate and alkali contents of samples. We have characterized the alkali-aggregate reactions of precoast concrete blocks from Hualien-Taitung seaside as the following. An irregular map crack, the depth of aggregate crack, the appearance of reactive gel and dark or pale reaction rims surrounding aggregates. Moreover, when the drilling core samples were tested using the uranyl acetate fluorescence method, the appearance of pale yellow-greenish fluorescence surrounding the cracks is evidence of the existance of reactive gel in the alkali-aggregate reaction. In summary, the deterioration of precast concrete blocks from Hualien-Taitung seaside is related to the alkali-aggregate reaction.
